Infectious diseases are one of the leading causes of death in the world. The problem of infectious diseases is exacerbated by the prevalence of multidrug-resistance in bacteria.1 Vancomycin is a glycopeptide antibiotic that has become drug of last resort to treat life-threatening bacterial infections such as those caused by methicillin-resistant S. aureus (MRSA).2,3 Vancomycin binds to D-Ala-D-Ala terminus of peptidoglycan pentapeptide of the bacterial cell wall, thus inhibiting transpeptidase-catalyzed cross-linking and maturation of the bacterial cell wall.2 However, bacteria have acquired resistance to vancomycin by alteration of cell wall precursors from D-Ala-D-Ala to D-Ala-D-Lac (vancomycin-resistant Enterococci, VRE), thickening of the cell wall (vancomycin intermediate resistant S. aureus, VISA) or sometimes modifying both (vancomycin-resistant S. aureus, VRSA).2,4,5 The alteration of the precursor is exhibited by five van genes and leads to manifold reduction in the binding constant of vancomycin to its target and results in loss of antibacterial activity.4 This perennial persistence of vancomycin resistance calls for urgent measures to develop more potent analogues. Hence, this persistent threat of drug resistance has triggered the scientific community all over the world to develop various strategies to tackle the problem. Currently, semi-synthetic glycopeptides; telavancin, dalbavancin and oritavancin are already approved for the treatment of skin infections caused by methicillin-resistant Staphylococcus aureus (MRSA).2 
Gram negative bacterial infections also pose an equal threat to human life. The WHO Global Report on Surveillance of Antimicrobial Resistance 2014 describes that gram negative bacteria like E. coli and K. pneumoniae have developed more than 50% of resistance to commonly used antibacterial drugs.6,7 More importantly, carbepenem-resistant bacteria, such as New Delhi Metallo β-lactamase-I (NDM-1) bacteria have become resistant to even last line of antibiotics, such as colistin.6,7 
Thus, there is an urgent need to develop novel strategy to overcome the resistance of gram positive bacteria. Also, it is vital to widen therapeutic options for the treatment of gram negative bacterial infections.